1. Field of the Invention
The present invention relates to spinal disorders and, more particularly, to a mobile dynamic system for treating spinal disorders.
2. Description of the Prior Art
Conventional implantable apparatuses for treating spinal disorders, such as scoliosis, typically include a pair of implantable rods for mounting on either side of the spinal column. Rigid transverse bars typically connect the rods together in spaced-apart parallel arrangement. Anchors in the form of hooks or screws are provided along each rod for anchoring same to the selected vertebrae. Once installed, the anchors are rigidly locked to the associated rod to prevent relative motion therebetween. Such an arrangement must be supplemented with bone grafts and the fusion of several vertebrae in order to prevent the apparatus from breaking due to the loads induced thereon. However, bone grafts and vertebrae fusion often cause serious complications throughout the patient""s adult life.
Accordingly, efforts have been made to develop implantable spinal instrumentation which could sustain greater loads and, thus, eliminate the need of resorting to bone grafts and vertebrae fusion. For instance, U.S. Pat. No. 5,672,175 issued on September 30, 1997 to Martin discloses a fusionless implantable spinal instrumentation wherein the implanted rods are anchored to the spinal column with fixed central anchors and terminal dynamic anchors. Each terminal anchor is rigidly connected to a coupling member which is in turn slidably mounted to a corresponding one of the implanted rods. The coupling members can have a selected number of degree of freedom relative to the corresponding rod.
Although the implantable spinal instrumentation disclosed in the above mentioned patent constitutes a technological advancement, it has been found that there is a need for a new dynamic implantable instrumentation which could be used for treating spinal disorders.
It is therefore an aim of the present invention to provide a dynamic mobile implantable apparatus for treating spinal column disorders.
It is also an aim of the present invention to provide such a dynamic mobile implantable apparatus which allows growth of the spinal column of the patient.
It is a further aim of the present invention to provide a new dynamic spinal instrumentation system.
It is a still further aim of the present invention to provide a dynamic spinal instrumentation system which is adapted to preserve at least in part the physiological mobility of the vertebrae and the disc.
It is still a further aim of the present invention to provide a new dynamic anchoring assembly for connecting a spinal implantable rod with a bone.
It is still a further aim of the present invention to provide a dynamic cross-link for structurally connecting a pair of spinal implantable rods together.
Therefore, in accordance with the present invention, there is provided a mobile dynamic internal system for treating a disorder of a spinal column having a sagittal plane, comprising at least one implantable correcting rod for mounting on one side of a patient""s spinal column, at least one fixed bracket rigidly mounted to said correcting rod, and at least one mobile carrier slidably mounted to said correcting rod, and first and second anchors respectively mounted to said mobile carrier and said fixed bracket for anchoring said correcting rod to the spinal column, wherein, once said dynamic internal system has been implanted, said first and second anchors still respectively have limited freedom of movement relative to said mobile carrier and said fixed bracket, thereby allowing said mobile carrier to slide along said correcting rod in response of movements of the spinal column.
In accordance with a further general aspect of the present invention, there is provided a mobile dynamic anchoring assembly for connecting an implantable rod with a bone, comprising a carrier adapted to be mounted to an implantable rod for sliding movement thereon and limited pivotal movement with respect thereto about an axis perpendicular to the rod, and a bone anchor articulately connected to said carrier for allowing the mobility of said carrier to be preserved once said anchor has been engaged with a bone.
In accordance with a further general aspect of the present invention, there is provided a mobile dynamic cross-link for structurally connecting a pair of implantable spinal rods together, comprising opposed first and second ends adapted to be connected to corresponding ones of a pair of implantable spinal rods, and a point of articulation between said first and second ends to prevent the implantable spinal rods from pivoting apart while allowing any other limited relative movements therebetween.